 计算n的阶乘
int main()
{
	int n;
	int multiplicative = 1;  // mulplicative 英语含义 乘法
	printf("计算阶乘:");
	scanf("%d", &n);
	for(int i = n; i > 0; i--)
	{
		multiplicative *= i;
	}
	printf("%d! = %d\n", n, multiplicative);
	return 0;
}

  计算1！+2！ +... 10！
int main()
{
	int multiplicative = 1;
	int sum = 0;
	for (int i = 1; i <= 10; i++)
	{
		multiplicative = multiplicative * i;
		sum += multiplicative;
	}
	printf("1! + 2! + 3! + ... + 10! = %d", sum);
	return 0;
}